Universal Serial Bus (USB) is a Master/Slave or Host/Device system in which there is only one host and one or more devices connected by cables to the host. A personal computer (PC) can have several USB ports and corresponding wires to connect the PC to its peripherals. Many different USB peripherals like mouse, keyboard, printer, scanner, hard disk, etc. can be connected to a single USB host controller residing on the personal computer. To connect a USB device to a different host controller (say another PC), the user unplugs the USB cable and establishes the connection physically by plugging the cable into the new host controller interface.